This study is designed to examine the use and costs of providing mental health services to enrollees in three provider plans: a large prepaid group practice, an independent practice association, and a traditional indemnity/service insurance plan. The population to be studied consists of Washington State employees. The study will include analyses of the relationship between mental health and somatic health services; an analysis of those who use mental health services including a comparison of the need for care and actual use; an examination of the effects of the three organizational forms represented by the plans and associated benefits, copayments, and limitations; adverse selection and switching between plans will also be included in the analyses; examination of issues of access to care and equity; and computation of population based rates of mental health services utilization. The study will use data collected in the State Employees Insurance Board Utilization study.